Abstract: In this paper we shall prove a basic relation between the Frattini subgroup of the generalized free product of an amalgam and the embedding of into nonisomorphic groups, namely, if can be embedded into two non-isomorphic groups and then the Frattini subgroup of is contained in . We apply this result to various cases. In particular, we show that if are locally solvable and is infinite cyclic then is contained in .

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